The 19-year-old star joked that she smokes "way too much weed" - slang for marijuana - when her pals presented her with a Bob Marley birthday cake at the bash at Beacher's Madhouse inside the Roosevelt Hotel in Los Angeles last week.

In a video obtained by website The Daily, she is seen saying: "You know you're a stoner when your friends make you a Bob Marley cake. You know you smoke way too much f***ing weed!"

Alluding to an incident last year when footage emerged of Cyrus smoking a bong water pipe, which she later claimed contained the legal hallucinogen Salvia, her pal Kelly Osbourne replied: "I thought salvia was your problem!"

A spokesperson for the former Hannah Montana star has denied she was referring to her own drug use in the video.

"It's all been taken out of context. The cake was a joke and Cyrus' response was intended to be sarcastic," they said.

Osbourne - who organised the bash for her friend - later took to her twitter page to defend the comments in the clip and slam the person who leaked the footage.

"Let me make something very clear after @MileyCyrus salvia incident we started calling her Bob Miley as a JOKE! The cake was also A JOKE," she wrote.

"It makes me sick that @Miley Cyrus so called 'friends' would sell her out and lead people 2 believe she is someone that she is not!